Cutting plate for a processing tool and holding device for such a cutting plate

ABSTRACT

Disclosed are a cutting plate for a processing tool, particularly a milling tool, and a holding device for such a cutting plate. Said cutting plate comprises at least one blade ( 1 ) which is configured in a radially protruding manner on a central body ( 5 ) of the cutting plate. The central body ( 5 ) is provided with a coupling part for mounting the cutting plate on a frontal seat of a shaft-type holding device ( 15 ) which defines a longitudinal axis. Said coupling part forms at least one driving surface transmitting an operating torque from the holding device ( 15 ) to the cutting plate. The inventive cutting plate also comprises a shaped part which forms a fixing device on the seat ( 17 ) of the holding device ( 15 ) in cooperation with an associated embodiment ( 35 ).

The invention relates to a cutting plate for a processing tool, a milling tool in particular, having at least one cutting edge configured to project radially from a central body of the cutting plate, this central body having, for the purpose of mounting the cutting plate on a frontal seat of a shaft-like holding device defining a longitudinal axis a coupling component which forms at least one driving surface for transfer of operating torque from the holding device to the cutting plate, and having a boring made in the central body so as to be concentric with the axis of rotation and designed and to secure the cutting plate axially in the seat of the holding device.

Cutting plates which, together with a shaft-like holding device which may be connected to a drive spindle or to a non-rotating machine support which may be controlled to execute adjustment movements, form a rotating or non-rotating machine tool, have been disclosed. DE 34 48 086 C2, for example, discloses a tool of this kind for inside machining. Tools such as this are widely used for machining processes which must be executed with high precision. In order to ensure adherence to correspondingly narrow tolerances it is extremely important to achieve strict coordination of cutting plate type and the holding device corresponding to it. In other words, care must be taken to make certain that there will be mounted on a particular holding device only cutting plates the body of which with its coupling component is adapted with precision to the geometry of the seat on the holding device. Consequently, in order to ensure optimal machining results the user must take great care to ensure that the only cutting plates used with a given holding device are ones which belong to an associated type classification which meets the corresponding specifications provided by the manufacturer for the cutting plate and the holding device. Even if the user does pay careful attention to this point, the possibility nevertheless exists that cutting plates not provided for use with this holding device may be mounted on the holding device.

The object of the invention is to provide a remedy for this situation in the form of a cutting plate for which it is ensured that only a desired optimal combination of cutting plate and holding device will be formed.

It is claimed for the invention that this object is attained for a cutting plate of the type referred to in the foregoing in that the cutting plate has a structural part which forms a non-interchangeability mechanism in conjunction with an associated configuration on the seat of the holding device.

This of necessity makes certain that the only cutting plates which may be mounted on a given associated holding device are ones with a specific structural part typifying the specification and forms part of the non-interchangeability mechanism.

In the case of cutting plates in which the coupling component has, as has already been disclosed, carrier components in the form of ribs projecting axially from the components, ribs which extend radially and on which the driving surface for the transfer of torque is configured, the structural part for the non-interchangeability mechanism may be configured on one of the ribs.

For example, a recess provided in the form of a flattening of the respective rib may be provided as structural part of the non-interchangeability mechanism.

A recess positioned on the cutting plate in an area between two ribs may be provided alternatively as a structural part of the non-interchangeability mechanism.

Another object of the invention is a holding device for cutting plates as claimed for the invention, a device characterized by configuration provided on the seat for the cutting plate such that a non-interchangeability mechanism is formed on the body of the cutting plate in conjunction with a structural part.

In one preferred exemplary embodiment this configuration may be in the form of an axial projection on the seat for the cutting plate, a projection which extends, when an associated cutting plate is mounted, into a recess made in the body, a recess which is provided on the cutting plate and a structural part of contact the non-interchangeability mechanism.

The axial height of the projection preferably is somewhat smaller than the depth of the recess in the associated cutting plate, so that the projection, which for example is in the form of an axially projecting pin on the seat of the holding device, on its outer end does not form a part of the surface of seat and cutting plate.

If the recess provided for engagement of the pin on the body of the cutting plate is in the form of a pocket bore, this bore preferably is dimensioned so that clearance is also obtained between the side walls of the pin and the pocket bore, and accordingly so that the pin may be seated in the pocket bore without coming in contact with the body of the cutting plate.

Reference will now be made in detail to the exemplary embodiments of the invention illustrated in the drawing, in which

FIG. 1 is a perspective view of a milling tool having a cutting plate with four cutting edges in one exemplary embodiment of the invention;

FIG. 2 is an enlarged and detached perspective view of the front end area of the milling tool shown in FIG. 1, the cutting plate being shown raised from the seat of the holding device;

FIG. 3 is a top view of the seat of the holding device of the milling tool on a scale smaller than that of FIG. 2;

FIG. 4 is a view of the cutting plate of the exemplary embodiment in the direction of the side of the cutting plate forming the coupling component;

FIG. 5 is a section along line V-V in FIG. 3;

FIG. 6 is a perspective view similar to that in FIG. 2 of a second exemplary embodiment of the invention;

FIG. 7 is a view of the cutting plate of the exemplary embodiment as viewed in the direction of the side of the cutting plate forming the coupling component; and

FIG. 8 a section of the second exemplary embodiment of FIGS. 6 and 7 similar to that of FIG. 5.

In the exemplary embodiment illustrated in FIGS. 1 to 5, which embodiment is that of a rotating milling tool having a machining axis of rotation 9, the cutting plate has four cutting edges 1 which are provided on the components 3 projecting radially from the body 5 of the cutting plate and which are displaced through an angle of 90° relative to each other. The body 5 of the cutting plate has a central bore 7 which is concentric with the machining axis of rotation 9 and has a boring section in the form of a tapering surface 11 (FIG. 2) widening toward the exterior. By means of a fastening screw 13, shown only in FIG. 1, having a conical section fitting on the tapering surface 1 the cutting plate may be screw-fastened by its frontal surface to a holding device 15 in the form of a milling cutter shaft. The holding device 15 has on its frontal surface a seat 17 for the cutting plate in the center of which seat there is provided a bore 19 concentric with the machining axis of rotation 9, the bore being provided with internal threading for the fastening screw 13. In its interior the shaft of the holding device 15 has flow channels for delivery of coolants/lubricants which are discharged by way of apertures 21 distributed over the circumference of the seat 17.

As shown particularly in FIG. 4, the body 5 of the cutting plate forms, on the side provided for mounting in the seat 17 of the holding device 15, a coupling component 23 with a circular end face 25 which extends perpendicularly to the axis of rotation 9. Extending axially from the plane of the end face 25 are three ribs 27 enclosing equal central angles relative to each other, these ribs 27 extending radially from the bore 7 to the circumference of the end face 25. Each rib 27 forms on one of its side flanks a driving surface for transfer of drive torque from the holding device 15 to the cutting plate. One of the ribs 27, in the example illustrated it being rib 27 positioned on the left in FIG. 4, has on its upper side a flattened part 29 so that there is formed on the upper surface of this rib 27 a recess which adjoins the bore 7. The recess formed by the flattened part 29 forms a structured part which forms a non-interchangeability mechanism in conjunction with a corresponding configuration which is provided on the seat 17 of the holding device 15.

As is to be seen in FIGS. 2 and 3, a rib-like annular surface 31 projecting a short distance axially is provided on the circumference of the seat 17 of the holding device 15. If the cutting plate is mounted on the seat 17 of the holding device 15, the end face 25 of the cutting plate is separated by a short distance from the annular surface 31. As is shown the most clearly in FIG. 2, grooves 33 are made in the frontal surface of the seat 17 which complement ribs 27 on the coupling component 23 of the cutting plate and in which these ribs are seated when the cutting plate is pressed against the holding device 15 by the screw 13. Support of the cutting plate and transfer of torque as a result of contact of the flanks of the ribs 27 with associated wall areas of the grooves 33 then ensue, a small amount of clearance remaining, as has already been pointed out, between the circumferential annular surface 31 and the end face 25.

FIGS. 2 and 3 show that a pin 35 extends axially from the bottom of the groove 33 in one of the grooves 33, in FIG. 3 this being the groove 33 positioned on the right. As shown in FIG. 5, the pin 35 extends into the recess formed in the body 5 of the cutting plate by the flattened part 29 of the associated rib 27 when the cutting plate is mounted on the seat 17 of the holding device. The axially measured height of the pin 35 and depth of the rib 27 formed by the flattened part 29 are dimensioned so that the pin 35 ends with a small amount of clearance between it and the flattened part 29; consequently, the end of the pin 35 does not form a part of the surface of contact of the body 5 of the cutting plate with the seat 17 of the holding device 15. The mutual local and dimensional association of the components on cutting plate and holding device forming the non-interchangeability mechanism, specifically, the structural part on the cutting plate formed by the flattened part 29 and the configuration of the seat 17 of the holding device 15 with a pin 35 projecting in the direction of the flattened part 29, forces formation of a failsafe device preventing the mounting of a “wrong” cutting plate on a holding device which is provided and configured exclusively for use of special cutting plates.

Structural parts other than the flattened part 29 shown and the projecting pin 35 could, of course, be provided on the holding device, as well as other configurations on the seat of the holding device obtaining the desired non-interchangeability effect could, of course, be provided.

FIGS. 6 to 8 show a second exemplary embodiment with a modified configuration of the non-interchangeability mechanism. As in the first exemplary embodiment, a pin 35 projecting from the seat 17 of the holding device 15 is provided as a component of the non-interchangeability mechanism associated with the holding device 15. Unlike the example first described, however, the pin 35 does not extend from the bottom of one of the grooves 33 but rather is positioned on the seat 17 in the area between two grooves 33. The recess provided for mounting of the pin 35 on the body 5 of the cutting plate accordingly is not provided as a flattened part of a rib 27 but is rather configured as a pocket bore 39 positioned between two ribs 27 on the coupling component 23.

As is to be seen in FIG. 8, the pin 35 and the pocket bore 39 are dimensioned with respect both to their axial extent and their thickness or width so that there is a gap on all sides between the surface of the pin 35 and the surface of the inside of the pocket bore 39. As FIG. 8 shows, the pin 35 is introduced into the pocket bore 39 without coming into contact with the body 5 of the cutting plate.

The invention has been described in the foregoing with reference to the example of rotating milling tools. It is obvious that the invention could be applied with a non-rotating tool such as a tool having a cutting edge on the cutting plate for inside machining of a rotating workpiece. 

1. A cutting plate for a processing tool, a milling tool in particular, which has at least one cutting edge (1) configured to project radially from a central body (5) of the cutting plate, which body has, for the purpose of mounting the cutting plate on a frontal seat (17) of a shaft-like holding device (15), a coupling component defining a longitudinal axis (9), a coupling component (23) which forms at least one driving surface for transfer of operating torque from the holding device (15) to the cutting plate, and which has a bore (7) concentric to the longitudinal axis (9) made in the central body (5) for a screw (13) securing the cutting plate axially on the seat (17) of the holding device (15), characterized in that the cutting plate has a structural part (29) which forms a non-interchangeability mechanism in conjunction with an associated configuration (35) on the seat (17) of the holding device (15).
 2. The cutting plate as claimed in claim 1, wherein a recess (29, 39) on the coupling component (23) extending in the axial direction is provided as a structural part of the non-interchangeability mechanism.
 3. The cutting plate as claimed in claim 1, wherein the coupling component (23) has at least one carrier component (27) projecting axially on the body (5), on which carrier component (27) the driving surface for transfer of torque is configured.
 4. The cutting plate as claimed in claim 3, wherein three carrier components in the form of axially projecting ribs (27) are present, which ribs, enclosing the same central angles relative to each other, extend radially and are provided for operation in conjunction with complementarily configured grooves (33) in the seat (17) of the holding device (15).
 5. The cutting plate as claimed in claim 4, wherein a recess formed by a flattened part (29) of one of the ribs (27) is provided as structural part of the non-interchangeability mechanism.
 6. The cutting plate as claimed in claim 4, wherein a recess (39) extending in the axial direction and positioned between two ribs (27) is provided on the coupling component (23) as a structural part of the non-interchangeability mechanism.
 7. A holding device for a cutting plate having the characteristics claimed in claim 1, characterized in that a configuration (35) is provided on the seat (17) for the cutting plate, which configuration forms a non-interchangeability mechanism in conjunction with a structural part (29) on the body (5) of the cutting plate.
 8. The holding device as claimed in claim 7 for a cutting plate as claimed in claim 4, wherein there is provided as a part of the configuration forming the non-interchangeability mechanism an axial projection (35) on the seat (17) for the cutting plate, which axial projection extends into the recess (29, 39) configured on the coupling component (23) of the cutting plate.
 9. The holding device as claimed in claim 8, wherein the axial height of the projection (35) is somewhat smaller than the depth of the recess (29, 39) on the coupling component (23) of the cutting plate.
 10. The holding device as claimed in claim 9, wherein there is provided as a part of the projection forming the non-interchangeability mechanism a pin (35) which extends axially from the seat (17) of the holding device (15) in parallel with the longitudinal axis (9).
 11. The holding device as claimed in claim 10, wherein the pin (35) is dimensioned to be smaller with respect to its axial length and its thickness than the associated recess (39), so that this pin (35) may be introduced into this recess (39) without coming into contact with the body (5) of the cutting plate. 